This invention relates to hay and grain harvesting machines, such as mower-conditioners and windrowers, of the type having a laterally elongated crop cutting header mounted by linkage to a mobile carrying frame and, more particularly, to an improved device for converting the normal lateral floatation mode of header suspension into a vertical floatation mode of suspension.
In machines of this type, the header is provided with gaging shoes which carry a portion of the weight of the header and gage the height of the cutting apparatus from the ground. It is generally considered preferable to have a suspension system providing lateral or radial floatation wherein the header is not constrained to remain parallel to the axes of the wheels on the carrying frame. Thus, if one side of the header is raised a limited extent, as by a gage shoe encountering an irregularity of obstruction, the other side of the header and its gage shoe will remain on the ground. However, there are conditions wherein lateral floatation is undesirable, such as in cutting grain, wherein the header is in a partially raised position off its gage shoes, and in sidehill operation, wherein the increased loading of the downhill gage shoe and the reduced loading of the uphill shoe can cause irregular stubble height control or shingling. These conditions require a means of locking out the lateral floatation and providing a more nearly vertical floatation wherein the header remains substantially parallel to the carrying frame wheel axes, that is, raise one side of the header and the other side is also raised.
Others have provided a radial floatation lockout device in a windrower wherein each of the lower suspension links is connected in a sort of four bar linkage to the respective end of a torque transmitting member mounted on the windrower chassis. The suspension links are thereby constrained to follow each other. Although this device performs its function, it requires several parts which, in addition to the added expense, increases the possibility of breakage or wearing out.